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Chapter 4. Plants. Lesson 1 How do leaves help a plant?. Leaves are organs made of cells and tissues Plants make their own food called glucose Leaves contain various tissues. Each tissue has a particular cells that perform certain roles
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Chapter 4 Plants
Lesson 1 How do leaves help a plant? • Leaves are organs made of cells and tissues • Plants make their own food called glucose • Leaves contain various tissues. Each tissue has a particular cells that perform certain roles • Leaves have openings in the bottom to let air in and out
Plants make their own food. • They are called PRODUCERS • Producers- organisms that make their own food. • Humans are consumers. • Consumers- CANNOT make their own food. • Most of a plant’s food is made in its leaves. • The top layer of a leaf is smooth and this protects the plant. • The bottom layer of a leaf looks like a sponge. • It has spaces that air can pass through.
Photosynthesis • The process in which plants make sugar for food • Plants perform photosynthesis by using: • Carbon dioxide • Water • Sunlight • Photosynthesis occurs in the chloroplasts • Chloroplasts make the plant green
Sunlight provides the cells the energy they need for photosynthesis. • A plant’s roots get the water. • The water enters the chloroplasts. • Carbon dioxide comes from the atmosphere (air). • Carbon dioxide enters the plant through its leaves (bottom). • Carbon dioxide then enters the chloroplasts. • The water and carbon dioxide combined are used to make sugar. • Photosynthesis makes OXYGEN for humans and animals. • Photosynthesis also makes GLUCOSE (sugar) for plants to grow. • This means that plants make glucose (sugar), their food, during the day. • They don’t use all of their food during the day; they save some for night time.
Cellular respiration- plants use oxygen with food to get the energy they need for growth, repairs, and reproduction • Sugar moves from the leaves to other parts of the plant where it is stored and later provides energy. It also forms cellulose, a chemical that makes up the strong cell walls. • Carbon dioxide + water + sunlight → oxygen + sugar
Lesson 2How do stems and roots help a plant? • Stems- plant organs that hold leaves, flowers, and fruit on a plant • Xylem and phloem tissues are tubes that transport substances within vascular plants
Stems • Leaves grow on stems. • Stems are plants’ organs (heart, kidney). • Stems help leaves get more sunlight. • Stems also hold fruit and flowers on plants. • Some stems have thorns (roses). • Thorns are a plant’s protection. • A thorn is a sharp point. • There are two kinds of stems: • Woody stems (trees and bushes) • Non-woody stems (dandelions)
Parts of a Stem • Inside a stem there are tubes that transport (carry) things: • Minerals • Water • Nutrients • There are two types of tubes: • Xylem • Phloem
Xylem • Tubes that carry AWAY water and minerals from the roots to the leaves. • The roots take water from the soil. • The water has minerals in it that came from the soil (like fertilizer). • Plants use these minerals for photosynthesis.
Phloem • These are tubes that carry sugar from the leaves to the rest of the plant. • In trees, the phloem is the innermost layer of the bark. • The bark protects the phloem.
Roots • Roots are plant organs • They grow in the ground • Roots are strong • They hold the plant in place • Roots also help the plant get WATER from the ground
Different Kinds of Roots • Taproots- a large root that grows straight down • Fibrous root- many roots grow out in all directions / the roots divide into smaller and smaller roots
Lesson 3 How do plants reproduce? • Parts of a flower: • Petals- colorful outer area of the flower • Stamen- the male part of the flower (a single flower may have many stamens) • Anthers- tissues at the top of each stamen (where pollen is located) • Filament- holds the anthers • Pistil- the female part of the flower (has a bottle-like shape) • Stigma- receives pollen during civilization • Ovary- female reproductive organ
Pollination • Pollination is the moving of pollen from the stamen to the pistil • But how is this possible if plants don’t move? • Wind, insects (bees), water, birds, and even bats can move pollen • Flowers attract these organisms to come and eat the flower • When they rub against the flower, stamen cells attach to them
When they go to another flower, they drop the pollen down to the pistil • They join with egg cells in the pistil • This is called fertilization (just like how babies are made) • DNA carries information about how a plants looks and works • The sperm cell has half of the male parent’s DNA • The egg has half of the female parent’s DNA • This DNA combined causes new plants to look similar to their parents
Seeds • Parts of a seed: • Seed coat- protects the embryo • Embryo- where the new plant is formed • Endosperm- surrounds the embryo • A seed has one or two cotyledons. Seeds of plants with one cotyledon are called monocots, while seeds of plants with two cotyledon are called dicots • http://www.brainpop.com/science/diversityoflife/seedplants/
Spreading Seeds • Seeds can be spread through a variety of ways • Animals • Humans • Wind • Water • Affects rate of plant growth: • DNA • Environment
Spores • Spores are single plant cells that are not fertilized like seeds, but can grown into a new plant. • Many plants reproduce asexually, (with only one parent) • Some plants can reproduce both sexually and asexually • There are some plants that are cones that contain seeds. These seeds are moved through wind, birds, insects, etc. and these help spread the seeds.